richard.p16
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MMU 2.0S What am I doing wrong, Problem found

Mar 17, 2019 3:03 am

Hello Everyone,
I got the MMU 2.0S built and installed.
I upgraded to the latest FW on both units.
I am assuming since I did the extruder upgrade my system is now a MK3S so when I updated the firmware I updated it to MK3S. Original system is a MK3.
System passes all self tests and will prints first layer and will print one color prints.

When I got print multi color prints nothing comes out and it thinks filament is coming out and starts the print. It loads all the filaments and I can see it down down to the printer head and does what looks like a purge and nothing comes out.
The Finda and IR are both set and I can run filament through and they work.

Also whenever the MMU powers on it sounds like a machine gun. Is this normal?
Thanks

Here is a link to the machine gun noise. It is not mine but mine makes the same noise.
https://www.youtube.com/watch?v=Z7a2qWxAcbQ

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None of the pre-sliced Gcode on Prusa's site for MMU worked. I sliced my own and they work????
Don't know why. Very frustrating that it took a day to figure this out.

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PJR
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Re: MMU 2.0S What am I doing wrong, Problem found

Mar 17, 2019 9:57 am

richard.p16 wrote:
Mar 17, 2019 3:03 am
I am assuming since I did the extruder upgrade my system is now a MK3S
But did you upgrade the extruder for MMU2S? Or did you simply use the magnets and ball for the IR sensor? If the latter, then you will need to also do the MMU2S extruder upgrade.
richard.p16 wrote:
Mar 17, 2019 3:03 am
Also whenever the MMU powers on it sounds like a machine gun. Is this normal?
That is the idler homing and is normal.

Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage or loss.

richard.p16
Posts: 190
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Re: MMU 2.0S What am I doing wrong, Problem found

Mar 17, 2019 2:23 pm

PJR wrote:
Mar 17, 2019 9:57 am
richard.p16 wrote:
Mar 17, 2019 3:03 am
I am assuming since I did the extruder upgrade my system is now a MK3S
But did you upgrade the extruder for MMU2S? Or did you simply use the magnets and ball for the IR sensor? If the latter, then you will need to also do the MMU2S extruder upgrade.
richard.p16 wrote:
Mar 17, 2019 3:03 am
Also whenever the MMU powers on it sounds like a machine gun. Is this normal?
That is the idler homing and is normal.

Peter
It's the full extruder upgrade with the new opto switch. I got it to start one print last night and now I am down again. :( Will try again tomorrow.

roy.r3
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Re: MMU 2.0S What am I doing wrong, Problem found

Mar 17, 2019 2:47 pm

I have been facing the same problems as you mentioned.
Here is what I did:

Make sure all Bondtech gears of the MMU are aligned correct.

Throw away the orange PTFE Boden Tube delivered from Prusa as its tolerances are very tight. Replace it with a tube having an inner diameter of 2.0 mm instead of 1.85. Once your MMU works, the orange Bowden gets problems with the thicker tips of the filament. The length of the new tube needs to be 360mm.

Check the Bowden on top of the hotend (I hope you replaced it with the new one as it needs to be shorter!), mine was somehow squeezed after one day and I replaced it by a Capricorn Tube. Check the correct length once again and don't forget to cut the inner taper on top and the outer taper which is going into the Hotend.

Since I did all this, filament change works like a charm, but facing a Pre Heat Error if I use filaments having different temperature settings. In my opininion this makes the MMU more or less useless. This is definitely a Firmware problem.

BR
Roy

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PJR
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Re: MMU 2.0S What am I doing wrong, Problem found

Mar 17, 2019 3:39 pm

richard.p16 wrote:
Mar 17, 2019 2:23 pm
It's the full extruder upgrade with the new opto switch. I got it to start one print last night and now I am down again. :( Will try again tomorrow.
It's an IR sensor. Did you use the ball and magnets, or have you printed and used all the MMU2S extruder upgrade parts including the sensor tower and idler door with sensor trigger arm?

Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage or loss.

roy.r3
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Re: MMU 2.0S What am I doing wrong, Problem found

Mar 17, 2019 5:07 pm

The new MMU2S comes together with the full Extruder upgrade.
Thus the printer is an Mk3S afterwards.

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PJR
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Re: MMU 2.0S What am I doing wrong, Problem found

Mar 17, 2019 7:07 pm

roy.r3 wrote:
Mar 17, 2019 5:07 pm
The new MMU2S comes together with the full Extruder upgrade.
Thus the printer is an Mk3S afterwards.
You are aware that there are different extruder parts for Mk3S and Mk3S+MMU2S ?

And that you cannot use a Mk3S with the MMU2S unless you install those different extruder parts? If you do, the symptoms will be exactly as reported, hence why I am asking the same question twice.

Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage or loss.

roy.r3
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Re: MMU 2.0S What am I doing wrong, Problem found

Mar 17, 2019 7:15 pm

I think the MK3S (infrared filament sensor) fits to MMU2S already. If you still have the version with the steel ball you need to upgrade them. But those items are included in the MMU2 S package ats it was in mine.
On my package of the MMU2S I got all parts to upgrade the MK3 to MK3S version.
As he just got his MMU2S he should have the items included to upgrade the MK3 as well.

richard.p16
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Re: MMU 2.0S What am I doing wrong, Problem found

Mar 18, 2019 1:03 am

roy.r3 wrote:
Mar 17, 2019 2:47 pm


Throw away the orange PTFE Boden Tube delivered from Prusa as its tolerances are very tight. Replace it with a tube having an inner diameter of 2.0 mm instead of 1.85. Once your MMU works, the orange Bowden gets problems with the thicker tips of the filament. The length of the new tube needs to be 360mm.



BR
Roy
I think your right about the orange tubing. I can print now but sometimes I get skipped layers. I think it is too tight tolerance on the ID and variance in the filament. I can feel sometimes that my filament goes through perfectly and other times it gets stuck and and I find a half moon or mouse bit out of the filament where it has been ground down in the MMU. I have some extra Bowden Tubing. I will have to check the ID.
Thanks

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